There are some risk factors for stroke that you can't control. Fortunately, there are many thar you can control. Here's which is which, and what you can do.

Risk factors you can't control:

Age
Age is an important predictor of stroke. As we age, the risk of stroke increases, especially after the age of 65.

Gender
Before they reach menopause, women have a slightly lower risk of stroke than men. Men older than 55 and women who are postmenopausal have the highest risk of stroke.

Family history
There are a few, very rare, inherited causes of stroke. But stroke is like most diseases in that having a close relative who has had a stroke increases your risk of stroke. More is gradually being learned about how genes predispose individuals to having a stroke.

Ethnic background
Ethnic background is a complex issue, since there are many different genetic and environmental differences between races. In addition, strokes occur for different reasons in different races. For example, it appears that the risk of stroke is slightly higher in people of First Nations, African, or South Asian backgrounds, largely due to a higher frequency of high blood pressure. Studies are ongoing to try to establish more firmly the reasons for the apparent differences.

Recent stroke or transient ischemic attack (TIA)
A recent stroke or transient ischemic attack (TIA) leads to a significant increased risk of stroke. It makes sense that if someone has already had a stroke or TIA there is risk of having another one. However, as time passes from the first event, the risk of a future stroke is reduced. As well, if the cause of the first TIA or stroke is found, the risk of a future stroke can often be reduced by treating the cause, and also by treating all other risk factors for stroke. See "Stroke: preventing recurrence" for more information about preventing a second stroke or TIA.

Risk factors you can control:

High blood pressure
High blood pressure (hypertension) is the most common risk factor for stroke. It is also an important cause of heart disease and other diseases.

It is important to control high blood pressure, regardless of how old someone is. It has been well established that treating blood pressure results in a dramatic reduction in the risk of stroke. An ideal blood pressure is less than 140/90 mm Hg, or 130/85 mm Hg if you have diabetes. Even if you have normal blood pressure, it is important to have it checked regularly to ensure that you do not develop high blood pressure.

High cholesterol
High cholesterol is a significant risk factor for heart disease and stroke. There are different types of cholesterol, including "good" cholesterol (called high-density lipoprotein or HDL) and "bad" cholesterol (called low-density lipoprotein or LDL).

High levels of cholesterol can lead to atherosclerosis, the buildup of plaque inside arteries. This narrows arteries and increases the risk of heart attack and stroke. Lowering cholesterol helps prevent heart disease and stroke.

Diabetes
If you have diabetes, you have an increased risk of stroke. The best way to lower your risk is to keep your blood sugar levels within your targets and address other risk factors you may have.

Atrial fibrillation
Atrial fibrillation (AF) is a well-known and significant risk factor for stroke. Atrial fibrillation is an abnormal heart rhythm or arrhythmia where the upper chambers (atrium) of the heart beat in a disorganized, chaotic manner. Since the contractions are not organized, a blood clot may form when the blood remains in the atrium too long and is not effectively "pumped" to the lower chamber of the heart (ventricle) and then to the rest of the body. This clot may then eventually dislodge and travel to the brain, causing a stroke.

If you have atrial fibrillation, you have 3 to 5 times as high a risk of having a stroke. Most people who have atrial fibrillation are prescribed an anticoagulant to help to reduce the risk of blood clots forming and causing a stroke.

Smoking
Smoking and second-hand smoke exposure increase your risk of many health problems, including stroke. It contributes to hardening of the arteries (atherosclerosis), increases the risk of blood clots, and makes your heart work harder. However, it is never too late to stop smoking! After stopping, the risk of heart attack and stroke will be reduced.

Excessive alcohol consumption
Modest amounts of alcohol have been shown to protect against heart disease and stroke; however, excessive alcohol intake can increase your risk. Women should limit their alcohol consumption to no more than 2 drinks per day or 10 a week, and men should limit alcohol to no more than 3 drinks a day or 15 per week.

Obesity
Obesity increases the risk of many diseases, including stroke. Some of the risk may be due to the fact that obese people tend to have other risk factors for stroke, including high blood pressure, diabetes, and high cholesterol.

Physical inactivity
While even a small amount of physical activity has been shown to reduce the risk of heart disease and stroke, the more activity you do, the better the health benefits you get. You should do at least 150 minutes of moderate-intensity physical aerobic activity (like bike riding) or vigorous-intensity activity (like jogging or running) each week. The most benefits are seen when you are active for more than 10 minutes at a time.

Excessive stress
Too much stress can increase your risk of stroke, but we don't know exactly why this happens. It may be that too much stress over a long period of time increases blood pressure and increases narrowing of the arteries from plaque buildup. Take our stress quiz to see what your coping style is and to get tips for managing stress.

Birth control pill
Years ago, birth control pills probably did increase the risk of stroke, but today's birth control pills have lower hormone levels and the risk of stroke is now thought to be the same or only minimally higher than if no birth control pills are taken. You are more at risk for stroke while taking birth control pills if you smoke, have high blood pressure, are older than 40, or have a blood clotting problem.